Electric switch.



PATENTED FEB. 19, 1907.

' o. E. BVBLETH. ELECTRIC SWITCH.

APPLICATION FILED JUNE 23,

2'5 good contact when the main blade leaves theA 35 in opening or'closing theswitc'h thernetal UNITED STATE-s PATENT OEEIOE CHARLES E. E'vE'LETn or SCHENECTADY, NEW vroRK, AssGNoRl To GEE- ERAL ELECTRIC. COMPANY, A CORPORATION OE REW YORK.

ELECTRIC SWITCH.

iro. 844,787.

Specification of Letters Patent.

gerentes ret.' is, i907.

' Application filed Jfuns 23,1908. Serial No. 162,773.'

Tov all whom t manly concern: v Be it known that I, CHARLES E. E-vELErH, l a citizen of the United States, residing at Schenectady, in the county of Schenectady, 5 vState of New York, have invented certain new and useful -Im rovements inv Electric Switches, of which t' e following is a specification. A

This invention relates, to switches'for conro trolling electric circuits; and itsobject is to improve the operation` of the switch andy prevent the deterioration of the secondary or. Aalxiliary contacts at which the arcing takes ace. .A r 5' p in switches for handling heavy currents' it l is customary to provide, 1n addition to .the main switch-blade andclip, a pair of second ary contacts, one of which'is composed of material having al high melting-point, such as zo carbon, said contacts bein varranged to close in advance of the main blaeand to open after it has left its clip, so thatA any arcing which occurs may be confined to the secondary con# tacts. Unless the secondary contacts are in clip there may be a sli ht burning of thecli'p.

Moreover, the repeate arcing has a tendency f to roughen the surface of the metal secondary contact. A i

3o The bject of my invention is to produce a4 goodpcontact between the secondary contacts whenthe blade leavesv the clip `and alsoyto provide one-lof the secondary contacts with an abradant, so that when they rub together.

ke t in good condition. n the accompanying drawings, Figure 1 is 1 a side elevation of a switch embodying my 4o improvements, the swith'being closed. Fig. 2 .is a' similar view, showing the switch in arcing position; and Fig. 3 is an end view of the. switch in thevp'osition shown inFig..V 2. The main blade 1 is pivoted to the hinge' 45 clip at 2 and closes in the clip 3f Secured to the main blade is a metal holder 4,'in which. is held a secondary contact 5,'1composed of some refractory conductor, such as carbon, l A resilient arm. 6 is attached to one side of 5o the clip Bgand supported on the arm is the yother secondary contact- 7, preferably a block of cop er. The cooperating faces ofthe two secon ary contacts vare curved, and their ar.

contact will be smoothed and' polished and rangement that at theinstant the ,y

main blade leaves the cli the contact area 55 and-pressure between the locks isat a maxin mum, they being pressed rmly together by the' spring-arm 6, as indicated in dotted lines in Fig. 1.. .Tins causes the' circuit through the secondary contacts to be of compara- 6r tively lo'W resistance and saves the clip being burned. -Q/lheh the switch has been opened far enough to'separate the' secondary contacts, the arcing occurs at points removed from the effective contact-surface, 65 taking-place atthe angle 8 of the'bloch 5 the tip 9 ofthe block. The actualcontac-tsurfaces are thus. reserved fromroughening,

and the carbon'b ockis ,therefore worn away 4but slowly but the contact-surfaces are lia- 7o ble to become smoked, and in order to polish them I referpto use in connection with the carbon block an abradant, preferably incor' porated in the carbon. A IniXture'oic carbon-` and carborundum or carbon and emery is'7 5 efficient, and when a block of such a mixture is dragged over the copper or other metal con'- tact 7 it cleans, smooths, -and polishes it, and thus-keeps it in condition to makegood elec trical Contact with the block 5. '8o The carbon or other block 5 `ispreferably soldered into the holder 4, so as to make a good 'electrical connection therewith. addition-to the soldering apin or rivet IO- .l may be used to'fasten the block and the 85 -holder together', so that when the switch- `opens an excessive overload, heating the carbon so hot that the solder melts, the pin. will hold the block in place until the solder can harden. The holder' is ysecured to4 the 9o switch-bladeby means of a -lange 11, in 'which is a hole through which passes the screw-threaded stud 12, which the removable'handle 13 is attache vto the pieceV 14 on the. end "of the blade "9,5, 511i accordance withthe patent statutes IW 'have describedthe principle of m invention, 'together with the apparatus W 'ch I now consider to represent thebest embodiment l thereof, butl desire to have it understood mo l that the apparatus shown is only illustrative and .that'the invention can be 4carried out by other means, being applicable to switches, cut-outs, circuit-breakers, and-al1 apparatusv for opening 'and closing an' electric circuit. A l' 1'05 What l claim as new, and desireto secure" by Letters Patent o-the United States, is-

n A. switchscontact consstingef a hereof geneous mixture of u. refractory conductor i 5. In a, switch, the combination With the :md an abradunt. main blade,- of a handle havingl L screw- 2. A switch-contact consisting of a'homothreaded stud7 and u holder for a secondary geneous mixture oll carbon and carhorundum. Contact provided with a ange having u hole 3. The combination with n, switch, of secthrough which said stud passes.. v ondary contacts, one of which consists of Inwtness whereofIhaYe hereunto set my ebhonogeneoue mixture of carbon and an i hand this 22d day ofJune, 1903. a ra ant. Y. f

4. In a switch, the combination with the i CHARLES E" EVELB FH' main blade and its removable handle, of a,- Witnesses: secondary Contact secured to said blade by i BENJAMIN B. HULLI HELEN ORFORD,

seid handle. l 

